Yeast Transcriptomics During Bioprocessing: A Powerful Tool in Cellulosic Ethanol Production and Process Optimization

Ananda Nanjundaswamy, Alcorn State University Co-Author(s): Keerthi Mandyam, Department of Agriculture, Alcorn State University; Vinayak Kapatral and Benjamin, Vaisvil, and Daniel Schmitt, Igenbio, Inc

Yeast, saccharomyces cerevisiae, is very critical for ethanol production and its performance determines whether a process is economical or not. At first glance, ethanol production appears simple with dosing of yeast to a sugar rich medium where yeast produces ethanol through a fermentation process. But a closer look reveals a much complex biochemical processes involved in ethanol production. During fermentation, yeast will be growing in a high solid medium in presence of inhibitors such as ethanol and furfurals. Also there will be mass transfer limitations such as depletion of oxygen which creates stress for the yeast. In order to optimize the ideal conditions for the yeast growth and ethanol production, it is critical to understand the yeast behavior at transcriptional level. The present study employed leading cellulosic feedstock miscanthus for ethanol production in a benchtop bioreactor. Samples were collected at 24, 48 and 72h and analyzed for yeast behavior during fermentation. Transcriptional analysis of yeast indicated that yeast behaves differently in different me points. Transcriptional information of important biochemical pathways as influenced by the fermentation conditions will be discussed.